Hi surg welcome to steemit. Hope you like it here
Oh and P.S: Tell me if i'm wrong, but if I get this right, you have STEEM Power to upvote things, which gives that upvote some portion of a pool of STEEM, which you can a. covert to steem power.
That is correct. You have two currencies beside Steem Dollar and Steem. Steem is the base cryptocurrency of the Steem Blockchain. Steem Dollar were meant to be pegged against the US Dollar but speculations actually drove the price higher than 1$. Steempower is as you say a measurment for the influence a user have on the platform. The more you have the more your vote is worth.
You find more Information in the FAQ
https://steemit.com/faq.html#What_is_the_difference_between_STEEM__STEEM_Power__and_Steem_Dollars
I hope i could help you out.
Many Greetz
RE: I decided to try out a thing called Steemit